On this day, the first sampling round in the slaughter line was performed once 22 pigs from the first batch had already been eviscerated and not before the beginning of the slaughtering as was foreseen. At this moment, three of the selected points in the slaughter line were already contaminated by Salmonella. Four of the five activities analysed resulted positive at any of the samplings, and Salmonella could be detected in six out of the 24 samples collected during the slaughtering of the monitored batches Six high Salmonella risk batches were slaughtered on day II. No Salmonella was detected in holding pens before the housing of the
monitored pigs, nor in any of the samples collected in the slaughter
line before the beginning of the activity on day II. Only two samples
from the slaughter line yielded positive (8.3%) in the samplings
performed throughout the slaughtering of the monitored batches.
On day III, five batches of moderate Salmonella risk were slaughtered.
Salmonella was isolated from three of the five monitored holding pens
before the entrance of the pigs. Similar to day II, no Salmonella was
detected in any of the samples collected from the slaughter line before
the beginning of the work. However, three samples (12.5%) from the
slaughter line were positive during the slaughtering of the monitored
batches.
The risk of finding a positive carcass was three times higher on day
III (19 positive carcasses) compared to the other two days, when the
proportion of Salmonella contaminated carcasses was similar, (7 and 5
positive carcasses for days I and II respectively) (χ2 = 11.57, p b 0.001;
RR = 3.22, 95% CI 1.63–6.25). No differences among days were
detected in the proportion of positive samples of the slaughter line
points evaluated during the slaughtering of the selected batches
(χ2 = 3.66, p = 0.16).